Method for Manufacturing an Integrated MEMS Transducer Device and Integrated MEMS Transducer Device

ABSTRACT

In an embodiment, an integrated MEMS transducer device includes a substrate body having a first electrode on a substrate, an etch stop layer located on a surface of the substrate, a suspended micro-electro-mechanical systems (MEMS) diaphragm with a second electrode, an anchor structure with anchors connecting the MEMS diaphragm to the substrate body and a sacrificial layer in between the anchors of the anchor structure, the sacrificial layer including a first sub-layer of a first material, wherein the first sub-layer is arranged on the etch stop layer, a second sub-layer of a second material, wherein the second sub-layer is arranged on the first sub-layer, and wherein the first and the second material are different materials.

This is a divisional application of U.S. application Ser. No. 17/288,267entitled “Method for Manufacturing an Integrated MEMS Transducer Deviceand Integrated MEMS Transducer Device,” which was filed on Apr. 23,2021, which is a national phase filing under section 371 ofPCT/EP2019/080091, filed Nov. 4, 2019, which claims the priority ofEuropean patent application 18207101.9, filed Nov. 19, 2018, all ofwhich is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to a manufacturing method of integratedMEMS transducers such as parallel plate capacitive transducers.

BACKGROUND

MEMS sensors are commonly employed in a wide range of applications suchas automotive, consumer, industrial and medical, as well as many otherapplications. MEMS devices typically comprise a suspended object whichis formed by removal of a sacrificial layer towards the end of themanufacturing process. Suspending an object requires well-controlledetching in order to remove the sacrificial layer. Commonly, forsuspending components of a MEMS device a sacrificial material subjacentto the component to be suspended is removed through hydrofluoric acid,HF, in particular through a HF vapor etch.

SUMMARY

Embodiments provide an improved method for manufacturing an integratedMEMS transducer device with low power requirements and high sensitivity.

Typically, sacrificial layers for fabricating a MEMS device consist of asingle material such as silicon dioxide, SiO₂, that is removed byemploying HF vapor, vHF, as an etchant. During this process, a catalyst,which usually is water or alcohol, is added in order to ionize the HFvapor and as a consequence to initiate and to maintain the etching ofthe sacrificial material:

SiO₂+2HF₂ ⁻+2AH⁺→SiH₄+2H₂O+2A

As is identifiable from the reaction equation above with Alcohol A as acatalyst, even though vHF etching constitutes a dry etching process,water, H₂O, is formed as a byproduct of the reaction. This waterlikewise acts as a catalyst for the etching process:

2HF+H₂O→H₃O⁺+HF₂ ⁻

SiO₂+2H₃O⁺+2HF₂ ⁻→SiF₄+4H₂O

In order to prevent an uncontrolled etch and hence to achieve an optimaletch result avoiding non-uniformities in etched surfaces, the amount ofwater formed during the entire etching process must be well controlled.

A conventional approach suggests the sacrificial layer removal at hightemperatures which, however, reduces the etch selectivity between thesacrificial material and that of an etch-stop layer, ESL, which istypically employed for terminating the etching process and thuspreventing unwanted etching of other layers and/or materials. This leadsto thick ESLs being required in order to avoid over-etching, which limitthe sensitivity of the MEMS transducer as the ESL typically remains onthe finalized product for protective purposes.

An alternative conventional approach is the employment of sacrificiallayer materials that are characterized by a low moisture content and alow etch rate such that only a small amount of water is formed duringthe etching process. However, this approach leads to a decreasedproduction volume and higher manufacturing costs.

To overcome the limitations of conventional manufacturing methods, theimproved method is based on the idea to suspend an object of thetransducer, such as a diaphragm or a membrane, by means of removing asacrificial layer that comprises sub-layers of different materials.These materials are chosen such that an optimal trade-off is achievedbetween water formed during the etching process and the etchingduration, wherein parameters of the etching process itself, such astemperature and/or HF concentration, are maintained compared to aconventional unilayer sacrificial layer removal.

The method for manufacturing a MEMS transducer device according to theimproved method comprises providing a substrate body with a surface anddepositing an etch-stop layer, ESL, on the surface. The method furthercomprises depositing a sacrificial layer on the ESL, depositing adiaphragm layer on the sacrificial layer, and removing the sacrificiallayer. Therein, depositing the sacrificial layer comprises depositing afirst sub-layer of a first material and depositing a second sub-layer ofa second material, wherein the first and the second material aredifferent materials.

The substrate body, for example, comprises a substrate of semiconductorsuch as silicon and may comprise active circuitry, for example anapplication-specific integrated circuit, ASIC, for readout purposesarranged on a surface or partially or completely within the substrate.

The etch-stop layer, ESL, is of a material with a lower etch rateregarding an HF etch, for example a dielectric such as Si-rich siliconnitride, silicon carbide, silicon carbonitride or aluminum oxide, and isdeposited on a surface of the substrate body. In order to maintainsufficient sensitivity, the ESL is typically deposited with a thicknessof 20 to 500 nm in a vertical direction perpendicular to the surface ofthe substrate body.

The sacrificial layer is deposited on the ESL, i.e. on a surface of theESL facing away from the substrate body, and comprises a first and asecond material that have a high selectivity compared to the material ofthe ESL regarding a vHF etch, i.e. a significantly higher etch ratecompared to the material of the ESL such as silicon-rich SiN. The firstand the second material of the sacrificial layer may differ from eachother such that the etching behavior during removal of the sacrificiallayer differs for the first and the second material. For example, theetch rate or the isotropicity of the etching is different. The first andthe second material differ from each other in terms of composition,moisture content and/or density, for instance.

The diaphragm layer comprises the object to be suspended and isdeposited on the sacrificial layer, i.e. on a surface of the sacrificiallayer facing away from the substrate body. For example, the object to besuspended is a MEMS membrane and comprises an electrode, such as a topelectrode, of a capacitive MEMS transducer. Compared to conventionalpiezo-resistive transducers, capacitive transducers are characterized bylow power consumption and high sensitivity and accuracy. The diaphragmlayer therefore may comprise an electrically conductive material such asmetals like tungsten, titanium and titanium nitride. In this context lopelectrode' refers to the electrode of a transducer arranged at thelargest distance from the substrate body in a vertical directionperpendicular to a main extension plane of the substrate body. Thedistance is determined by the combined thickness of the ESL and thesacrificial layer and is typically in the order of 200 nm to 5 μm.

In contrast to conventional transducer devices that employ Si-baseddiaphragms, which have to be manufactured separately from the readoutcircuit due to the temperature requirements, an advantage of thesuggested materials enables a combined monolithic CMOS-compatiblefabrication of the entire transducer device without the requirement ofbonding wires that may produce additional noise and therefore limit thesensitivity.

Manufacturing a MEMS transducer device following the improved methodenables a well-controlled removal of the sacrificial layer forsuspension of the diaphragm and therefore prevents over-etching of theESL which may result in possible exposure of underlying structures andmaterials.

In some embodiments, the first sub-layer is deposited on the ESL and thesecond sub-layer is deposited on the first sub-layer.

In this configuration, the etchant that usually attacks the surface ofthe sacrificial layer facing the diaphragm layer, for example throughopenings in the diaphragm layer, first removes the second sub-layerbefore being able to etch the first sub-layer. This arrangement of thefirst and the second sub-layers forming a stack therefore furtherincreases the control over the etching process as thicknesses of thefirst and the second sub-layer may be predetermined in order to optimizethe etching of the first and the second sub-layer for a specifictransducer design.

In some embodiments, the first and the second material are dielectricssuch as oxides.

Like the aforementioned material choices for the ESL, oxides such assilicon dioxide are CMOS-compatible materials, which provide therequired high selectivity compared to the material of the ESL regardingan HF-based etch. In a vHF etching process, silicon dioxide ischaracterized by a 20 to 100 times higher etch rate compared tosilicon-rich silicon nitride, for instance. This allows for efficientremoval of the sacrificial layer without the necessity of providing athick ESL in order to prevent over-etching. For example, a thickness ofthe ESL is an order of magnitude smaller than a thickness of thesacrificial layer.

In some embodiments, the first and the second material differ from eachother in terms of an etch rate regarding a release etchant such as vHFor water-based HF acid.

The different etch rates of the first and the second material provide atrade-off between the well-controlled removal of the sacrificial layerand an acceptable total etching time required to remove the entiresacrificial layer. The different etch rates are realized by differentmoisture contents or densities of the first and the second material, forinstance. The denser material or the material with the lower moisturecontent produces less water as a by-product and therefore leads to alower etch rate compared to the material with the higher moisturecontent or the lower density material. Moreover, the material with thelower moisture content or higher density may be etched moreisotropically compared to the material with the higher moisture contentor lower density due to less water being formed and acting as a catalystleading to an uncontrolled etching behavior.

In some embodiments, the second material is an undoped silica glass,USG.

Undoped silica glass, deposited by low density CVD techniques, containssignificant moisture content leading to a high etch rate once theetching process is initiated. In embodiments, in which the etchantattacks the second sub-layer before the first sub-layer, a USG as thesecond material may lead to a fast removal of the second sub-layerbefore the etch becomes well-controlled during the removal of the firstsub-layer. Furthermore, water residues left after removal of the secondsub-layer may increase the initial etch rate of the first material,which has a low moisture content or higher density, for example.

In some embodiments, the first material is a fluorinated silica glass,FSG, or a silica glass being deposited via high-density plasma chemicalvapor deposition, HDP-CVD.

A PECVD deposited doped silica glass, such as FSG that has a fluorinedopant concentration of around 3.5% and is typically used as a low-κdielectric, and an HDP-CVD deposited silica glass are two alternativesto achieve a deposited dielectric layer with low moisture content andhigh density. In embodiments, in which the first sub-layer is depositedon the ESL and therefore etched last, such a slow etching first materialleads to a well-controlled etch behavior during the final stage ofremoving the sacrificial layer. Compared to USG, for example, a releaseetch of FSG or HDP-CVD deposited silica is significantly more isotropicand therefore prevents non-uniformities of the ESL after the releaseetch.

In some embodiments, the sacrificial layer is deposited with a thicknessof the sacrificial layer in a vertical direction, which is perpendicularto the main plane of extension of the substrate body, of equal to orless than 5 μm, in particular equal to or less than 1 μm.

As mentioned above, typically the distance of the diaphragm from thesurface of the substrate body is in the order of merely a fewmicrometers in order to maintain a sufficiently large sensitivity of thetransducer device. As it is desirable that the ESL is as thin aspossible, e.g., significantly thinner than 1 μm, said distance issubstantially determined by the thickness of the sacrificial layer. Fora sacrificial layer of 1 μm thickness, the first sub-layer may have athickness of 650 nm and the second sub-layer may have a thickness of 350nm, for instance, in order to achieve the aforementioned trade-off.

In some embodiments, depositing the sacrificial layer further comprisesdepositing a third sub-layer of a third material, wherein the thirdmaterial is different from the first and the second material, orcorresponds to the first material.

Some material choices of the diaphragm layer, for example titanium ortitanium nitride, are not entirely resistant to HF-based acids, suchthat the diaphragm layer may be attacked during the sacrificial layerremoval. To prevent the etching of the diaphragm layer, a thirdsub-layer of a material with a low etch rate may be deposited such thatthe diaphragm layer is deposited on said third layer. The thirdmaterial, like the first material, is an FSG or a HDP-CVD depositedsilica, for example. To maintain the material list of the manufacturingprocess as short as possible, the third material ideally corresponds tothe first material and has a likewise low moisture content and higherdensity.

In some embodiments, the substrate body comprises a passivation layerand/or an electrode layer, and the surface is a surface of thepassivation layer and/or the electrode layer.

The bottom electrode of a capacitive transducer, i.e. the electrodearranged closest to the substrate body, may be realized by depositing,patterning and structuring an electrode layer, for example comprising ametallic material, such that the ESL is deposited on the surface of theelectrode layer facing away from the substrate body. In order to preventshort-circuits, a passivation layer may in addition be deposited on thesubstrate body. For example, the passivation layer comprises adielectric material.

In some embodiments, the method further comprises patterning andstructuring the diaphragm layer, in particular prior to removing thesacrificial layer.

In order for the vHF etchant to be able to attack the top surface of thesacrificial layer, openings in the diaphragm may be formed, for exampleto create a perforated membrane. These openings may be designed in termsof size, shape and spacing, for instance, to adjust the etching behaviorof the sacrificial layer. Said openings therefore act as inlet ports ofthe etchant.

In some embodiments, depositing the diaphragm layer comprises depositingan adhesion layer.

As some materials, such as tungsten, are characterized by a low adhesionto other materials such as oxides, the adhesion can be promoted by anadditional adhesion layer, for example comprising titanium and/ortitanium nitride. To this end, depositing the diaphragm layer comprisesdepositing the adhesion layer on the sacrificial layer, followed bydepositing a layer of tungsten, for instance, which is used as the topelectrode in a capacitive transducer due to its electric conductivity.

The object is further solved by an integrated MEMS transducer devicefabricated after the method according to one of the embodimentsdescribed above. The device comprises the substrate body having a firstelectrode on a substrate, a suspended MEMS diaphragm with a secondelectrode and an anchor structure with anchors connecting the MEMSdiaphragm to the substrate body.

The anchor structure, for example, comprises vias or trenches forelectrically interconnecting the second electrode, i.e. the topelectrode, with active circuitry arranged on or within the substratebody.

In some embodiments, the integrated MEMS transducer device furthercomprises the sacrificial layer in between the anchors of the anchorstructure.

Spacings inside the anchor structure are inaccessible for the etchantduring the sacrificial layer removal. The finalized transducer device inthese embodiments therefore possesses residues of the sacrificial layercomprising the material stack of the sub-layers.

Further embodiments of the integrated MEMS transducer device becomeapparent to the skilled person in the art from the embodiments of themanufacturing method described above.

The object is further solved by a pressure sensor comprising anintegrated MEMS transducer device according to one of the embodimentsdescribed above.

The object is further solved by an electronic device comprising apressure sensor with an integrated MEMS transducer device according toone of the embodiments described above.

Applications of the integrated transducer device manufactured after theimproved method include environmental sensors such as capacitive CMOSpressure sensors, dynamic pressure transducers employed as microphonesand/or speakers in the audio band and for ultrasound applications.Furthermore, said transducers may be employed in micro-hotplates and forinfrared-detection. Electronic devices, in which the integratedtransducer devices may be employed, include mobile communication devicessuch as smartphones and tablet computers, but also wearable devices likesmartwatches.

BRIEF DESCRIPTION OF THE DRAWINGS

The following description of figures of exemplary embodiments mayfurther illustrate and explain aspects of the improved method.Components and parts of the integrated transducer device with the samestructure and the same effect, respectively, appear with equivalentreference symbols. In so far as components and parts of the transducerdevice correspond to one another in terms of the function in differentfigures, the description thereof is not repeated for each of thefollowing figures.

FIGS. 1A to 1E show cross sections of intermediate steps of an exemplaryembodiment of the improved manufacturing method of an integratedtransducer device;

FIGS. 2A to 2F show cross sections of intermediate steps of a furtherexemplary embodiment of the manufacturing method of an integratedtransducer device;

FIG. 3 shows a cross section of a finalized integrated transducer devicemanufactured with the improved method; and

FIGS. 4A to 4E show cross sections of intermediate steps of aconventional manufacturing method of an integrated transducer device.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

FIGS. 1A to 1E show cross sections of intermediate steps of an exemplarymanufacturing method of an integrated transducer device. In thisembodiment, depositing the sacrificial layer 3 comprises depositing afirst sub-layer 4 and a second sub-layer 5.

FIG. 1A shows a cross section of an intermediate product of a transducerdevice before the release etch. The integrated transducer devicecomprises a substrate body 1 of a substrate material, which may besilicon. The substrate body 1 may also comprise an integrated circuit,which may in particular be a CMOS circuit with active and passivecircuitry. Such integrated circuits are known per se, and are not shownin the figures. The integrated circuit may especially be provided for anevaluation of signals from the transducer, such as a capacitance of thetransducer.

A cover layer 2, which may include a wiring embedded in an inter-metaldielectric layer and/or a passivation, for instance, is applied on asurface of the substrate body 1. The inter-metal dielectric layer maycomprise silicon dioxide, and the passivation may comprise a combinationof silicon dioxide and silicon nitride, for instance. The part of thetransducer device that includes the substrate body 1 and the cover layer2 may be similar to a conventional semiconductor device with anintegrated circuit. The transducer device differs from such asemiconductor device by an arrangement of transducer elements on asurface of the cover layer 2 facing away from the semiconductor body 1.A thickness of the cover layer 2 may be in the order of 100 nm-5 μm, oreven 100-200 nm.

An electrode layer 7 may be arranged on the surface of the cover layer 2facing away from the substrate body 1 and patterned and structured, forexample via lithography and etching, in order to form a first electrodeof a transducer, especially a capacitive transducer, for instance. Thefirst electrode of such a transducer may be referred to as the bottomelectrode. An etch-stop layer, ESL, 8 is arranged on a surface of theelectrode layer 7 facing away from the substrate body 1. Thicknesses ofthe electrode layer 7 and the ESL 8 may be in the order of 20-500 nm, oreven 50-300 nm.

A sacrificial layer 3 is arranged on a surface of the ESL 8 facing awayfrom the substrate body 1. The ESL 8 is made of a material with asignificantly lower etch rate regarding a fluorine-based etchantcompared to a material of the sacrificial layer 3. For example, the ESL8 comprises silicon nitride, such as silicon-rich silicon nitride, whilethe sacrificial layer 3 comprises silicon or silicon dioxide. Thesacrificial layer 3 comprises a first and a second sub-layer 4, 5,wherein the first sub-layer is of a first material and arranged on thesurface of the ESL 8 and the second sub-layer 5 is of a second materialand arranged on the first sub-layer 4. The first material may befluorinated silica glass, FSG, which is characterized by a low moisturecontent compared to the second material, which may be an undoped silicaglass, USG, for instance. A total thickness of the sacrificial layer maybe in the order of 200 nm-5 μm, or even 500 m to 3 μm.

A diaphragm layer 6 is deposited on a surface of the sacrificial layer 3facing away from the substrate body 1 and patterned and structured in asubsequent step for forming openings 10. The diaphragm layer 6 maycomprise a sequence of layers and may particularly include a main layerand an adhesion layer. The latter is configured to facilitate thearrangement of the diaphragm layer 6 on the sacrificial layer 3. Amaterial of the adhesion layer may be characterized by a larger adhesionto the sacrificial layer 3 compared to a material of the main layer. Theadhesion layer may for example comprise titanium, titanium nitride, TiN,or a combination of titanium and TiN. The main layer may be a metal suchas tungsten. The thickness of the diaphragm layer 6 may be in the orderof 50 nm-2 μm, or even 50-300 nm. Parameters, such as size and spacing,of the openings 10 have to be considered when choosing both thicknessesof the first and the second sub-layer 4, 5 of the sacrificial layer 3,as this may influence the etching process.

In the following FIGS. 1B to 1E, the labeling is omitted forillustration purposes.

The shading of the respective layers is kept consistent throughout allfigures.

FIG. 1B shows a cross section of the intermediate product according toFIG. 1A after initiating the release by introducing the vHF etchantthrough the openings 10 of the diaphragm layer 6. As the secondsub-layer 5 possesses significantly higher moisture content compared tothe first sub-layer 4, the etch rate for the former is significantlyhigher.

FIG. 1C shows a cross section of the intermediate product according toFIG. 1B after the second sub-layer 5 has been completely removed. Due tothe low moisture content, the first sub-layer 4 shows, if at all, onlyminor decrease in thickness due to the etch. Since the diaphragm layer 6is fully released already at this point, the vHF etchant is able toattack the entire surface of the first sub-layer 4 facing away from thesubstrate body 1 enabling an isotropic etch, as illustrated in FIG. 1E,which shows a first sub-layer 4 with reduced thickness.

FIG. 1E shows a cross section of the intermediate product according toFIG. 1D after also the first sub-layer 4, and therefore the entiresacrificial layer 3, has been completely removed. The ESL 8 remains onthe finalized transducer and serves as protective layer for theotherwise exposed electrode layer 7.

In contrast to the embodiment shown in FIGS. 1A to 1E, a reverse orderof the sub-layers 4, 5 is likely possible. This case, in which the firstsub-layer 4 is characterized by a faster etch rate compared to thesecond sub-layer 5 regarding a specific etchant, may be employed ifprotection of the diaphragm layer has to be considered, while the ESL 8may have a high enough selectivity such that a well-controlled etch isnot crucial at this point. For example, the first sub-layer 4 may inthis embodiment comprise USG and the second sub-layer 5 may compriseFSG. The thicknesses of the sub-layers 4, 5 in this embodiment may betailored to the specific design and/or manufacturing process.

FIGS. 2A to 2F show cross sections of intermediate steps of a furtherexemplary manufacturing method of an integrated transducer device.Compared to FIGS. 1A to 1E, in this embodiment, depositing thesacrificial layer 3 further comprises depositing a third sub-layer 9 onthe second sub-layer 5.

FIG. 2A, analogous to FIG. 1A, shows a cross section of an intermediateproduct of a transducer device before initiating the release etch. Thisembodiment is particularly relevant if the diaphragm layer comprises anadhesion layer of Ti and or TiN, for example. The adhesion layer notonly promotes adhesion of the main layer to the sacrificial layer 3, butTitanium also acts as a getter material that reduces the partialpressure of hydrogen in the cavity, i.e. the void between the ESL 8 andthe diaphragm layer 6. For this reason, etching of the adhesion layerand consequent formation of TiF₄ residues should be avoided. To thisend, the third material of the third sub-layer 9 like the firstsub-layer 4 is characterized by a low moisture content resulting in alow etch rate. For example, the first and the third material is HDP-CVDsilica glass.

In the following FIGS. 2B to 2F, the labeling is omitted forillustration purposes. The shading of the respective layers is keptconsistent throughout all figures.

FIG. 2B shows a cross section of the intermediate product according toFIG. 2A after initiating the release by introducing the vHF etchantthrough the openings 10 of the diaphragm layer 6. After etching throughthe third sub-layer 9, the second sub-layer 5, comprising USG, ispreferentially etched, as also illustrated in FIGS. 2C and 2D. Due tothis preferential etching, the third sub-layer 9 substantially coversthe diaphragm layer 6 after the second sub-layer 5 has been completelyremoved.

FIG. 2E shows a cross section of the intermediate product according toFIG. 2D after the second and the third sub-layer 5, 9 have beencompletely removed and the thickness of the first sub-layer 4 issignificantly decreased.

FIG. 2F shows a cross section of the intermediate product according toFIG. 2E after also the first sub-layer 4, and therefore the entiresacrificial layer 3, has been completely removed. Like in the embodimentof FIG. 1E, the ESL 8 remains on the finalized transducer.

FIG. 3 shows a cross section of a finalized integrated transducer devicemanufactured after an embodiment of the improved method. The transducerdevice comprises a structured electrode layer 7 arranged on a coverlayer 2, with the electrode layer 7 forming a bottom electrode of thetransducer and contacts for the diaphragm layer 6. The electrode layeris completely covered with an ESL 8 facing away from the substrate body1 owing to the improved manufacturing method described in the previousfigures. The diaphragm layer 6 constitutes a perforated MEMS membrane,for example, having a main layer 6B arranged in between an adhesivelayer 6A and a protective layer 6C, protecting the main layer 6B duringthe release etch on both surfaces of the main layer 6B. The diaphragmlayer 6 is interconnected with contact pads of the electrode layerand/or contacts of circuitry of the substrate body, for instancebelonging to an integrated circuit, via anchors ii of an anchorstructure.

As the sacrificial layer 3 in between individual anchors is sealed fromthe cavity that is delimited by the ESL 8, the diaphragm layer 6 and theanchor structure, the release etch does not remove said portion of thesacrificial layer 3, which therefore remains in between said anchors inthe finalized transducer. The FIG. 3 further shows a cap layer 12deposited after the release etch serving as a protective layer of thetransducer.

FIGS. 4A to 4E FIGS. 2A to 2F show cross sections of intermediate stepsof a conventional manufacturing method of an integrated transducerdevice. The conventional method employs a sacrificial layer 3 consistingof a single unilayer, for example of USG. The procedure of the releaseetch is analogous to that shown in FIGS. 1A to 1E and 2A to 2F. Theunilayer results in an anisotropic etch, i.e. faster etching in avertical direction towards the substrate body 1 compared to the etchrate in lateral direction parallel to a main plane of extension of thesubstrate body 1. This anisotropic etch results in an uneven removal ofthe sacrificial layer and may cause uneven removal of the ESL 8, whichmay in turn influence the capacitance between the top and bottomelectrode and hence decrease the sensitivity.

The embodiments shown in the FIGS. 1A to 3 as stated represent exemplaryembodiments of the improved manufacturing method and the integratedtransducer device, therefore they do not constitute a complete list ofall embodiments according to the improved method. Actual transducerdevice configurations may vary from the embodiments shown in terms ofshape, size and materials, for example.

Although the invention has been illustrated and described in detail bymeans of the preferred embodiment examples, the present invention is notrestricted by the disclosed examples and other variations may be derivedby the skilled person without exceeding the scope of protection of theinvention.

1. An integrated MEMS transducer device comprising: a substrate bodyhaving a first electrode on a substrate; an etch stop layer located on asurface of the substrate; a suspended micro-electro-mechanical systems(MEMS) diaphragm with a second electrode; an anchor structure withanchors connecting the MEMS diaphragm to the substrate body; and asacrificial layer in between the anchors of the anchor structure, thesacrificial layer comprising: a first sub-layer of a first material,wherein the first sub-layer is arranged on the etch stop layer, and asecond sub-layer of a second material, wherein the second sub-layer isarranged on the first sub-layer, and wherein the first and the secondmaterial are different materials.
 2. The integrated MEMS transducerdevice according to claim 1, wherein the first material comprises atleast one of a lower moisture content or a higher density compared tothe second material.
 3. The integrated MEMS transducer device accordingto claim 1, wherein the first and the second material differ from eachother in terms of an etch rate regarding vapor hydrofluoric acid orwater-based HF acid.
 4. The integrated MEMS transducer device accordingto claim 1, wherein the first and the second material are dielectrics.5. The integrated MEMS transducer device according to claim 1, whereinthe first and the second material are oxides.
 6. The integrated MEMStransducer device according to claim 1, wherein the second material isan undoped silica glass.
 7. The integrated MEMS transducer deviceaccording to claim 1, wherein the first material is at least one of afluorinated silica glass or a silica glass.
 8. The integrated MEMStransducer device according to claim 1, wherein a thickness of thesacrificial layer in a vertical direction, which is perpendicular to thesurface of the substrate, is equal to or less than 3 μm.
 9. Theintegrated MEMS transducer device according to claim 1, wherein athickness of the sacrificial layer in a vertical direction, which isperpendicular to the surface of the substrate, is equal to or less than1 μm.
 10. The integrated MEMS transducer device according to claim 1,wherein the sacrificial layer further comprises a third sub-layer of athird material, and wherein the third material is different from thefirst and the second material or corresponds to the first material. 11.The integrated MEMS transducer device according to claim 1, wherein thesubstrate body comprises a cover layer; and wherein the surface is asurface of the cover layer.
 12. The integrated MEMS transducer deviceaccording to claim 11, wherein the first electrode is arranged on a sideof the cover layer that faces away from the substrate.
 13. Theintegrated MEMS transducer device according to claim 1, wherein theanchor structure comprises vias or trenches configured for electricallyinterconnecting the second electrode with an active circuitry arrangedon or within the substrate body.
 14. The integrated MEMS transducerdevice according to claim 1, wherein the integrated MEMS transducerdevice further comprises a cap layer, the cap layer directly adjoiningthe second electrode and the etch stop layer.
 15. A pressure sensorcomprising: the integrated MEMS transducer device according to claim 1.16. An electronic device comprising: the pressure sensor according toclaim 15.